Disease Unit Flashcards
Virus
An infectious agent that kills host cells and can result in tissue damage, organ failure and death. It weakens the immune system so other pathogens infect the host. It can’t replicate without a host organism. Examples include: HIV, influenza and herpes
Bacteria
Secretes toxins that harm or kill the host. It replicates independently from the host organism and can replicate inside or outside the host cell. Examples include: Tuberculosis, tetanus and cholera
Fungi
Secrete enzymes that digest skin, nails and hair. They can lead to respiratory infection people with weakened immune systems and they can secrete toxins that harm the host. Bacteria replicate independently from the host. Examples include: ringworm, meningitis and pneumonia.
Parasite
Damages the host cells, tissue and organisms. They block the movement of materials inside the body and remove vitamins and minerals from food before the host can absorb them. It replicates independently from the host cell and can replicate within or outside of it. Examples include: malaria, parasitic worms and toxoplasmosis.
Protist
Damage the host cells causing illness, symptoms of the infection often kill the host. It replicates independently of the host organism. Examples: Giardiasis, cyclosporiasis and malaria.
Prion
A type of protein that can trigger normal proteins in the brain to fold abnormally. It replicates in the host. Examples: Mad cow disease, creutzfeldt-jakob disease and scrapie
Cleanliness
Hygienic stuff like washing and dry hands, covering your mouth and nose with a tissue when sneezing or coughing. Food hygiene like cleaning surfaces, chopping boards, utensils, pots, pans, dishes and storage containers.
Sanitation
Cleaning surfaces like kitchens and bathrooms properly to stop the spread of diseases.
Social distancing
Preventing the spread of a contagious disease by maintaining a physical distance between people and reducing the number of times people come into close contact with each other.
Isolation/Quarantine
Keeps people with the disease away from their community and the rest of the population. It is effective in preventing the spread of the disease because it removes the carrier from the population preventing interactions with others.
Immunisation
Allows immunity to develop without exposure to the disease itself. It stimulates your body’s immune system to produce antibodies which fight and kill the virus. If you come into contact with this virus again, your body will be prepared to fight it.
Antibiotics
Chemicals that work by killing or reducing the growth of bacteria. It is effective in blocking processes in bacteria, killing the bacteria or stopping them from multiplying. This helps the body’s natural immune system to fight the bacterial infection. Examples include: penicillin and amoxicillin
Antiseptics
A group of chemicals that kill microbes on the outside of the body. It is effective in stopping the growth of microorganisms on the skin. They’re used daily in medical settings to reduce the risk of infection and stop the spread of germs. Examples include: hydrogen peroxide and antibacterial dye
Disinfectants
Group of chemicals that kill microbes on surfaces, floors and toilets. They’re important to use because disease and bacteria can live on surfaces.
Second line of defence - Innate immunity
The main purpose of this systems response is to immediately prevent the spread and movement of foreign pathogens throughout the body.
Third line of defence - The adaptive system
This system has a memory that allows it to better defend the animal from pathogens it has encountered before. It is also very specific, has a slow response time, develops throughout an animal’s lifetime and has specific responses to certain pathogens.
Physical Barriers - Skin
The outer layers of skin contain keratin, and microorganisms cannot penetrate it unless it is broken. It has its own population of normally harmless bacteria. Their presence helps keep invading pathogens from multiplying. If the skin is broken, the blood-clotting mechanism very quickly forms a seal across the wound to prevent the entry of pathogens.
Examples of Physical Barriers
The mucous membranes produce mucus that trap microbes. Hair within the nose filters air containing microbes, dust, pollutants. Cilia lines the upper respiratory tract traps and propels inhaled debris to throat. Urine flushes microbes out of the urethra
Second line of defence - Non Specific Responses
Inflammation response - A response to when tissue is damaged, such as by the invasion of a pathogen. The area becomes red, hot, swollen and painful, this is due to the blood circulation to the area being increased. This helps confine the pathogen while an increased number of white blood cells destroy the pathogen
Second line of defence - Phagocytosis
White blood cells that actively move from the blood to tissues where they ingest and destroy any foreign material including pathogens
B Cells
White blood cells from the bone marrow that when activated create antibodies against invading bacteria and viruses.
T Cells
White blood cells from the thymus that when activated produce substances that attack infected host cells.
Memory Cells
These cells are able to recognize antigens which enter the body a 2nd time. They can provide instant defence so the antigen can be eliminated quickly, sometimes before any symptoms.
Third line of defence - Active immunity
The immunity to a pathogen that occurs following exposure to said pathogen. When the body is exposed to a disease, B cells create antibodies that assist in destroying or neutralizing the disease agent.
Passive Immunity
This is provided when a person is given antibodies to a disease rather than producing them through his or her own immune system. A newborn baby acquires passive immunity from its mother through the placenta.
The difference between antigens and antibodies and how they interact to form immunity to disease.
Antigens are molecules capable of stimulating an immune response. Antibodies are Y-shaped proteins produced by B cells of the immune system in response to exposure to antigens. Antibodies bind to the antigens to help eliminate the pathogen.
Antibodies
Y-shaped proteins made by your immune system’s B lymphocytes or B cells. B cells attack and eliminate viruses and other toxins outside the cell. They do this by making specific antibodies for a single type of antigen. These lock on to their specific antigens and tag them for attack. They also block these antigens, keeping them away from your healthy cells. Their purpose is to kill antigens, stopping infection.
Third line of defence - Acquired immunity
Immunity that the body develops after it overcomes a disease, or through immunization
What is a disease?
A condition with specific symptoms that reduces health by altering how an organism functions.
What is an infectious disease?
A contagious illness caused by pathogens transmitted between hosts. Examples include; measles, chicken pox or the flu.
What is a non-infectious disease?
An illness caused by lifestyle, genetics and environmental factors. It is not contagious. Examples include; cancer, cardiovascular disease and diabetes.
What do pathogens seek?
They seek to reproduce and spread to new hosts. They’re an infectious agent that causes diseases or illness in an organism.
What are examples of direct transmission?
Skin to skin (direct transmission through close physical contact), droplets (direct transmission through mucus that comes from the nose or mouth) and body fluids (direct transmission through the exchange of fluids like blood).
Examples of droplet transmission
Sneezing directly on to another person, and drops of mucus coming into contact with their mucous membrane
Examples of body fluid transmission
Touching the blood of another person when you have an open wound on your hand or coming into contact with body fluids during sexual contact
Examples of skin to skin transmission
Touching the fluids released when someone scratches or bursts blisters on their skin.
Branches of immune system
There are two branches of the immune system: the innate and the adaptive immune system. The innate immune system is rapid, but non-specific in its response, whereas the adaptive immune system is slower, but specific. The two systems work together. Almost all white blood cells belong to the innate immune system. The two cells that belong to the adaptive immune system are B and T cells.
How Does Your Immune System Recognize Harmful Agents?
Harmful agents are recognized through antigens, which are any substance that elicits an immune response. The adaptive immune system utilizes MHC molecules to identify the presence of a harmful agent. They can kill the infected cell, neutralize the harmful agent, or recruit more immune cells. The innate immune system utilizes PRRs such as the Toll-like receptors to identify structural components of the harmful agent.
Barrier defences
A part of the body’s most basic defence mechanisms. It is not a response to infections, but are continuously working to protect against a broad range of pathogens. Examples include: skin, mucous membranes, tears, earwax, mucus, and stomach acid.
First line of defence - Chemical Barriers
Mucus - Within the body’s digestive, respiratory, reproductive and urinary tracts our bodies produce a thick slimy mucus that acts as a method of preventing the physical entry of pathogens. Tears -Contain a chemical that inhibits bacterial growth. Stomach acid - due to the stomach’s highly acidic nature it kills pathogens. There are populations of harmless microorganisms in the vagina. They act on cells shed from the walls of the vagina to create acid conditions which inhibit the growth of some bacteria and fungi. Urine is a sterile, acid fluid. It flushes the ureters, bladder and urethra and helps prevent the growth of microorganisms.
Tregs
These T cells play a role in regulating or suppressing other immune cells.
Natural active immunity
Immunity that results from natural exposure to a pathogen.
Artificial active immunity
Immunity that results from the deliberate introduction of weakened or disabled pathogens into the body
Attenuated pathogen
Pathogens that have had their disease-causing ability removed and/or are not able to replicate in human cells
Indirect Transmission
When the spread of disease through an intermediate vehicle. This means the disease may be transmitted by animal or insect vectors through the air, food or water, or by inanimate objects. Examples include: Food borne transmission, waterborne transmission, airborne transmission, vector borne transmission and contaminated objects
Direct transmission
When a disease is spread from person to person whether it’s through skin to skin contact, droplets or fluids.
Physical Barriers - Respiratory tract - Nasal Cavity
The hairs and mucus within the nasal cavity traps pathogens and can trigger the body’s reaction to sneeze. Coughing and Sneezing- both actions are a result of the cilia being agitated and are human reactions to expel any foreign particles or agents
